Tablet computer-based robotic system

ABSTRACT

An example robotic chassis may include a frame including a first side member and a second side member connected by a transverse member near respective first ends of first side member and the second side member. The robotic chassis may also include a rigid case having a mounting point for a tablet computer. The rigid case may be rotatably coupled between the side members near respective second ends of the side members. The robotic chassis may further include a first arm and a second arm having respective distal ends and respective proximal ends. Respective proximal ends of the first arm and the second arm may be rotatably coupled to the frame near opposite respective first ends of the first side member and the second side member. In addition, the robotic chassis may include a plurality of wheels rotatably coupled to the frame.

BACKGROUND

Robotic devices may include control systems that are communicativelycoupled to various sensors. For instance, an example robot may includeone or more of an accelerometer, an inertial measurement unit, or a GPSsensor, which may generate data that the control system may use forvarious tasks, such as navigating an environment. The example robotdevice may also include a camera, illumination (from a device such as anLED), a speaker, and a microphone, which may be used for variousapplications, such as surveillance, telepresence, or search and rescue.

Like robotic devices, tablet computers may include control systems thatare communicatively coupled to various sensors. For instance, an exampletablet computer may include one or more of an accelerometer, an inertialmeasurement unit, or a GPS sensor, which may generate data that thecontrol system may use for various tasks, such as mapping. Tabletcomputers may also include one or more cameras (e.g., a front-facing anda rear-facing camera), which may be used for various applications, suchas photography or video conferencing.

SUMMARY

An example robotic system may include a robotic chassis and a tabletcomputer. The robotic chassis may include a mounting point for thetablet computer, such that the tablet computer may be mounted on therobotic chassis. Various components of the robotic system may rotatearound parallel axis, which may facilitate various operations of therobotic system. For instance, a rigid case that includes the mountingfor the tablet computer may rotate about a first transverse axis betweentwo side members of a frame of the robotic chassis. Additionally, insome implementations, one or more arms may rotate about a secondtransverse axis. The first transverse axis and the second transverseaxis may be located at opposite ends of the frame, which may providefacilitate positioning the robotic chassis in various configurations.

In one example implementation, a robotic chassis may include a framehaving a first side member and a second side member connected by atransverse member near respective first ends of first side member andthe second side member. The robotic chassis may also include a rigidcase having a distal end and a proximal end and a mounting point for atablet computer. The proximal end of the rigid case may be rotatablycoupled between the side members near respective second ends of the sidemembers. The robotic chassis may further include a first arm and asecond arm having respective distal ends and respective proximal ends.Respective proximal ends of the first arm and the second arm may berotatably coupled to the frame near opposite respective first ends ofthe first side member and the second side member. In addition, therobotic chassis may include a plurality of wheels rotatably coupled tothe frame.

In another example implementation, a plan to move a robotic chassis to atarget position may be determined. The target position may include atarget orientation of a tablet computer. Based on the determined plan, arotation of a rigid case having a proximal end that is rotatably coupledbetween respective side members of the robotic chassis at respectivefirst ends of the side members may be initiated between the side membersabout a first transverse axis. After initiating the rotation of therigid case about the first transverse axis, the implementation mayinvolve determining that the tablet computer is at the targetorientation based on data from at least one orientation sensor of atablet computer. In response to determining that the tablet computer isat the target orientation, the implementation may involve halting therotation of the rigid case about the first transverse axis to positionthe tablet computer in the target orientation.

Another example implementation may involve determining a target positionfor a rigid case having a proximal end that is rotatably coupled betweenside members of a frame of the robotic device at respective first endsof the side members. The target position may include a target height ofthe rigid case from a support surface and a target angle between therigid case and the support surface and the rigid case may include amounting point for a tablet computer. The implementation may involvecausing the rigid case to rotate between the side members about a firsttransverse axis to orient the rigid case at the target angle between therigid case and the support surface. The implementation may involvecausing a first arm and a second arm that are rotatably coupled to therobotic device at the respective second ends of the side members torotate outside the side members and downward towards the support surfaceabout a second transverse axis that is parallel to the transverse memberand to the first transverse axis to lift the rigid case upwards to thetarget height of the rigid case from the support surface.

Another example implementation may include a means for determining aplan to move a robotic chassis to a target position that includes atarget orientation of a tablet computer. Based on the determined plan,the implementation may include a means for initiating a rotation of arigid case having a proximal end that is rotatably coupled betweenrespective side members of the robotic chassis at respective first endsof the side members between the side members about a first transverseaxis. The implementation may also include a means for determining thatthe tablet computer is at the target orientation based on data from atleast one orientation sensor of the tablet computer. The implementationmay further include a means for halting the rotation of the rigid caseabout the first transverse axis to position the tablet computer in thetarget orientation.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a simplified block diagram illustrating components of anexample robotic system.

FIG. 2A is a perspective view of an example robotic system in a firstconfiguration.

FIG. 2B is a perspective view of the example robotic system in a secondconfiguration.

FIG. 2C is a perspective view of the example robotic system in a thirdconfiguration.

FIG. 3A is a deconstructed view of the example rigid case 206 in whichthe example rigid case is coupled to the robotic chassis.

FIG. 3B shows an example arrangement in which a front shell of the rigidcase is hinged to a rear shell of the case.

FIG. 3C shows the example arrangement where a tablet computer is placedin the rear shell.

FIG. 4 is a flow chart illustrating an example method for positioning atablet computer in a target position.

FIG. 5 is a perspective view of the example robotic system in a fourthconfiguration.

FIG. 6A is a side view of an example robotic system in a first stage ofa sequence.

FIG. 6B is a side view of the example robotic system in a second stageof the sequence.

FIG. 6C is a side view of the example robotic system in a third stage ofthe sequence.

FIG. 7A is a perspective view of an example robotic system and a targetlocation.

FIG. 7B is a perspective view of an example robotic system at the targetlocation.

FIG. 8 is a flow chart illustrating another example method forpositioning a tablet computer in a target position.

DETAILED DESCRIPTION

Example methods and systems are described herein. Any exampleimplementation or feature described herein is not necessarily to beconstrued as preferred or advantageous over other implementations orfeatures. The example implementations described herein are not meant tobe limiting. Certain aspects of the disclosed systems and methods can bearranged and combined in a wide variety of different configurations, allof which are contemplated herein.

Furthermore, the particular arrangements shown in the figures should notbe viewed as limiting. Other implementations might include more or lessof each element shown in a given figure. Further, some of theillustrated elements may be combined or omitted. Yet further, an exampleimplementation may include elements that are not illustrated in thefigures.

An example robotic system may include a robotic chassis and a tabletcomputer. The robotic chassis may include a mounting point for thetablet computer, such that the tablet computer may be mounted on therobotic chassis. When arranged in the mounting point of the roboticchassis, the tablet computer may perform various functions on behalf ofthe robotic system. For instance, the tablet computer may controlaspects of one or more sub-systems of the robotic device, such as alocomotion system or a sensing system. Alternatively, the tabletcomputer may include one or more sensors and may capture sensor data byway of such sensors. Such sensor data may facilitate various operationsof the robotic system, such as navigating an environment. In some cases,the robotic system may be implemented using a commercially availabletablet computer. Such a tablet computer may provide a convenientcomputational and/or sensing platform for the robotic system.

In some implementations, the robotic chassis may include a frame thathas various members. For instance, the frame may include two sidemembers. The side members may be connected by one or more transversemembers extending between the side members. In one instance, the framemay include a first side member and a second side member connected by atransverse member near respective first ends of the first side memberand the second side member, which may form a U-shaped frame.

One or more wheels may be connected to the frame. The wheels may bedriven by one or more actuators, which may facilitate navigating therobotic system around an environment. In some implementations, thewheels may be configured with tracks, which may improve traction in somecircumstances.

The robotic chassis may include a rigid case, which may include themounting point for the tablet computer. In some instances, the rigidcase may include a front shell and a rear shell that, when connectedtogether, define an interior volume in which a tablet computer may bearranged. The front shell and the rear shell may be connected using anysuitable connection mechanism, such as one or more latches.

The rigid case may be rotatably coupled about a transverse axis betweentwo side members of the frame of the robotic chassis, such as the firstside member and the second side member noted above. The rigid case maybe rotatable 360 degrees about the transverse axis, perhaps driven byone or more actuators (e.g., one or more electric motors). Thetransverse axis may extend from between respective second ends of theside members, opposite the transverse member (e.g., between the tips ofthe U-shaped frame).

Rotatably coupling the rigid case about the transverse axis may haveseveral advantages. For instance, rotation of the rigid case mayreposition sensors of the tablet computer. In one example, the tabletcomputer may include a camera, and rotation of the rigid case may changethe viewing angle of the camera lens. Additionally, rotating the rigidcase may shift the center of gravity of the robotic system and/orsupport an end of the frame on the rigid case, which may facilitatenavigation around an environment. For instance, rotating the rigid casemay assist the robotic system in navigating over obstacles.

The robotic chassis may include one or more arms that are rotablycoupled to the frame. The arms may rotate about another transverse axisthat is parallel to the traverse axis about which the rigid case mayrotate. In some implementations, the arms may rotate outside of thefirst and second side members. This arrangement may allow both the armsand the rigid case to rotate 360 degrees concurrently without cominginto contact with one another. The arms may facilitate navigation aroundthe environment.

Rotation of the arms and/or the rigid case may facilitate moving therobotic system to a target position. For instance, the tablet computermay determine a target position, which may include a target orientationand/or a target height of the tablet computer. The robotic system mayrotate the rigid case, one or more of the arms, and one or more of thewheels to move the computer to the tablet position. Sensors of thetablet computer may generate positioning data, which may facilitatedetermining that the tablet computer is in the target position.

The robotic chassis may include various features that may enhance theruggedness of the robotic system. For instance, the rigid case mayinclude one or more gaskets that increase the water-resistance of thetablet computer. The chassis may include various impact absorbingmaterials, such as shock absorbing wheels, tracks, or bumpers. Further,the chassis may be composed of one or more durable materials, such as arigid plastic or a metal, such as aluminum.

In some cases, the robotic system may be communicatively coupled to asecond tablet computer. The second tablet computer may include atouchscreen or other suitable input interface. The second tabletcomputer may detect input at the touchscreen that indicates variouscommands for the robotic system. The second tablet computer may thentransmit these commands to the robotic system, which may cause therobotic system to perform various operations. Further, a camera onrobotic system may stream video to the second tablet computer. Thesecond tablet computer may display the streamed video on the touchscreenor another graphical interface, thereby providing a view from aperspective of the robotic system.

In some cases, the robotic system may be communicatively coupled withmultiple other instances of the robotic system. A particular one of theinstances may control certain aspects of the behavior of the otherrobotic systems in the swarm. For instance, a tablet computer mounted inthe mounting point of the particular robotic system may provide controlsto modify one or more operations of the robotic systems in the swarm.

Referring now to the figures, FIG. 1 is a simplified block diagramillustrating components of an example robotic device 100. The roboticdevice 100 may include a control system 102, a sensing system 110, acommunication system 112, and a locomotion system 114. One or more ofthese components may be interconnected by a bus or other interconnectionsystem 116. Each of these systems may be divided into one or morecomponents, which may be physically located in a tablet computer or arobotic chassis, among other possibilities.

The control system 102 may include one or more processors 104,non-transitory data storage 106, and program instructions 108 stored onthe data storage 106. The one or more processors 104 may, for example,include a single or multi-core processor, an application specificintegrated circuit (ASIC), field programmable gate array (FPGA), and/orany other suitable circuitry. The program instructions 108 stored on thedata storage 106 may be executable by the one or more processors 104 toperform specific operations, which may include the specific operationsdescribed herein. In some implementations, robotic system 100 mayinclude multiple instances of control system 102, which may becommunicatively coupled with one another. For example, a first tabletcomputer may include a first instance, a second tablet computer mayinclude a second instance, and a robotic chassis may include a thirdinstance of control system 102. Other examples are possible as well.

The sensing system 110 may include sensors arranged to sense aspects ofthe environment in which the robotic system 100 is operating. Thesensing system 110 may connect to the control system 102 and therebyprovide the control system 102 with data from the sensors. The controlsystem 102 may track and store this sensor data and make operationaldeterminations based on the tracked sensor data. Sensors of sensingsystem 110 may be physically located on the tablet computer or on therobotic chassis. Some commercially available tablet computers includesensors that may have application to a robotic system, such as anaccelerometer, a global positioning system (GPS) sensor, or a camera,among other examples of sensors. Such sensors may be communicativelycoupled to a processor of the tablet computer, such that the processormay receive data generated by the sensors.

The sensing system 110 may include one or more position, velocity, oracceleration sensors. For instance, the sensing system 110 may includean accelerometer. While an accelerometer may be included in a tabletcomputer for various tasks such as drop detection or screen rotation,the accelerometer may facilitate navigation and other tasks when thetablet computer is incorporated into a robotic system. Alternatively,the sensing system 110 may include an inertial measurement unit (IMU).The inertial measurement unit may sense the robotic device's velocity,orientation, and acceleration. The sensing system 110 may furtherinclude one or more global positioning system (GPS) devices, which maybe used in mapping applications on the tablet computer. As part of therobotic system, the GPS may sense the absolute position of the roboticsystem. The control system 102 may use GPS data to determine the roboticsystem's speed or direction, possibly in combination with data from anIMU or accelerometer.

The sensing system 110 may include one or more perception sensorsarranged to sense the environment in which the robotic system 100 isoperating. As part of the tablet computer, such sensors may be used inphotography or video conferencing applications. Incorporated into therobotic system 100, such sensors may sense physical features of theenvironment, such as the terrain, vegetation, man-made objects andstructures, and the like. For instance, the sensing system 110 mayinclude one or more cameras that may generate imaging data of theenvironment in which the robotic system is operating. In operation, oneor more stereo cameras may generate three-dimensional images of thephysical features of the environment. The control system may evaluatethe three-dimensional images to identify the physical features and theirposition relative to the robotic system. In some implementations, theperception sensors may include one or more lidar systems. Such lidarsystems may generate data indicating a map or model of the physicalfeatures of the environment, which may then be used by the controlsystem to navigate the robotic device, perhaps in combination withsensor data from the other sensors. The perception sensors may alsoinclude one or more range finders, such as one or more laser rangefinders, which may generate data indicating distances from the roboticdevice to the physical features of the environment. The sensing system110 may include other types of perception sensors as well.

The communication system 112 may include one or more wired or wirelesscommunication interfaces that operate according to one or morecommunications protocols to facilitate data communications amongcomponents of the robotic system (e.g., between the tablet computer andthe robotic chassis) and between the robotic system and other systems(e.g., between the tablet computer of the robotic system and a tabletcomputer used as a control device for the robotic system). For example,the communication system 112 may include a Wi-Fi communication componentthat is configured to facilitate wireless data communication accordingto one or more IEEE 802.11 protocols. Alternatively, the communicationsystem 112 may include a cellular radio communication component that isconfigured to facilitate wireless communication (voice and/or data) witha cellular wireless base station to provide mobile connectivity to anetwork. Further, the communication system may include a BLUETOOTH®communications component. Many other communication interfaces are knownand available and the robotic system may include any suitablecommunication interface now known or later developed.

The locomotion system 114 may include one or more wheels. In someimplementations, the locomotion system may include four wheels. The fourwheels may include two left wheels coupled to a first side member andtwo right wheels connected to a second side member. The right wheels andthe left wheels may be linked with respective tracks. The tracks mayfacilitate navigating over uneven terrain, such as terrain that includesobstacles. The four wheels may be connected at respective ends of theside members, such that the locomotion system 114 includes two frontwheels and two rear wheels. The locomotion system 114 may furtherinclude one or more actuators, which may drive one or more of thewheels. In some examples, the one or more actuators may include electricmotors, perhaps operated by a battery mounted on the robotic system 100.

FIG. 2A is a perspective view of an example robotic chassis, which maybe an instance of the robotic system 100 of FIG. 1. Robotic chassis 200includes a frame, a rigid case 206, arms 208A and 208B, and wheels 210A,210B, 210C, and 210D, as shown.

The frame includes a first side member 202A, a second side member 202B,and a transverse member 204 connecting the first side member 202A to thesecond side member 202B at respective first ends of the first sidemember 202A and the second side member 202B. The frame may be composedof a variety of materials, such as plastic or metal. In some cases,members of the frame may be fully or partially hollow, such that themembers define volumes in which various components such as actuators,communications interfaces, sensors, and/or power storage systems (e.g.,batteries) may be contained. In some implementations, the first sidemember 202A, the second side member 202B, and the transverse member 204may be chosen such that they are narrower than the diameter of thewheels 210A, 210B, 210C, and 210D, as shown. Such a design may allow therobotic system to operate (e.g., navigate) after flipping over.

As further show in FIG. 2A, the rigid case 206 is rotatably coupledbetween the first side member 202A and the second side member 202B atrespective first ends of the first side member 202A and the second sidemember 202B. The rigid case 206 may rotate about a first transverse axisthat is parallel to the transverse member 204. One or more actuators mayrotate the rigid case. Such actuators may be located within side member202A and/or side member 202B, among other alternatives.

Further, the rigid case 206 has a first end that is rotatably coupled tothe first side member 202A and the second side member 202B (i.e., aproximal end). Such a configuration allows rotation of the rigid case206 in a circular pattern having a radius that is approximatelyproportional to a length of the rigid case 206. The length of the rigidcase 206 extends from the proximal end of the rigid case 206 to a distalend of the rigid case 206 that is opposite the proximal end. In otherimplementations, the rigid case 206 may be coupled to the first sidemember 202A and the second side member 202B at various other locationsalong the length of the rigid case 206 and along respective lengths ofthe first side member 202A and the second side member 202B.

The rigid case 206 may include a mounting point for a tablet computer.The mounting point may include any suitable arrangement of components tohold the tablet computer. For instance, as noted above, the rigid case206 may include a front shell and a rear shell that, when connected,define a volume that may contain the tablet computer. The front shelland the rear shell may be connected by latches, screws, or any suitableconnection system.

In some cases, the rigid case 206 and/or the frame may be sized to thedimensions of a given tablet computer. For instance, a width of therigid case 206 extends approximately from the first side member 202A tothe second side member 202B, as shown. Further, the length of the rigidcase extends approximately from the first transverse axis to thetransverse member 204. In this arrangement, the first side member 202A,the second side member 202B, the transverse member 204, and the firsttransverse axis define a volume though which the rigid case may rotate,thereby allowing the rigid case 206 to rotate 360 degrees about thefirst transverse axis. In other implementations, the mounting point maybe configured to accommodate tablet computers having differentdimensions.

As noted above, rotation of the rigid case 206 about the firsttransverse axis may have various advantages. For instance, rotation ofthe rigid case 206 may reposition the tablet computer, which may in turnreposition one or more sensors of the tablet computer. Rotation of therigid case 206 may also cause a shift in the center of gravity of therobotic chassis 200, which may facilitate navigating an environment.Further, rotation of the rigid case 206 may bring the rigid case 206into contact with a support surface or other feature of the environment.Further rotation may support the respective second ends of the firstside member 202A and the second side member 202B above the supportsurface or feature, which may assist in navigating over the supportsurface or past the feature. For instance, in some circumstances, therobotic chassis 200 may become hung-up or caught on a feature of theenvironment and rotation of the rigid case 206 may assist in freeing therobotic chassis 200 from the feature.

The arms 208A and 208B are rotatably coupled to the frame (inparticular, to respective axles of wheels 210A and 210D, as shown). Asshown, the arms 208A and 208B rotate about a second transverse axis thatis parallel to the transverse member 204 and to the first transverseaxis. In some implementations, arms 208A and 208B may rotateindependently, perhaps driven by respective actuators. As noted above,the arms 208A and 208B are rotatably coupled to respective axles ofwheels 210A and 210D. Such axles may include respective axle shafts(which may contain all or part of the actuators that drive the arms 208Aand 208B), respective proximal axle ends that are coupled to the sidemembers, and respective distal axle ends to which the arms 208A and 208Bare rotatably coupled.

The arms 208A and 208B extend from respective proximal ends that arecoupled to the frame to respective distal ends. The length of each armfrom the proximal end to the distal end is approximately the same lengthas the first side member 202A and the second side member 202B. Thissizing may have several advantages. For instance, as shown, arms 208Aand 208B do not extend past wheels 210B and 210C when aligned parallelwith the first side member 202A and the second side member 202B, whichmay protect the arms 208A and 208B should the robotic chassis 200 fallon the wheels 210B and 210C in certain ways.

The wheels 210A, 210B, 210C, and 210D rotate about respective axles. Oneor more actuators may rotate one or more of wheels 210A, 210B, 210C, and210D. Rotation of the wheels may cause the robotic chassis 200 tonavigate around the environment. A control system of the robotic system,such as control system 102, may cause the wheels to move the roboticchassis 200 to various locations, such as a target location, perhapsbased on data from one or more sensors (e.g., a GPS, IMU, oraccelerometer). Wheels 210A and 210B are linked by a first track.Likewise, wheels 210C and 210D are linked by a second track. Such tracksmay improve traction in some circumstances, among other possiblebenefits.

FIG. 2A illustrates the robotic chassis 200 in an instance of a “stowed”configuration. In the stowed configuration, the rigid case 206 and thearms 208A and 208B are approximately parallel to the first side member202A and the second side member 202B. Such a configuration may allow therobotic chassis 200 to operate after flipping over or navigate undercertain obstacles overhanging the support surface, among other possibleadvantages.

A control system, such as control system 102, may cause the roboticdevice to transform into the stowed configuration. Such a transformationmay involve rotating the arms 208A and 208B next to and substantiallyparallel with the side members 202A and 202B, as shown. Thetransformation may further involve rotating the rigid case next to andsubstantially parallel with the first side member and the second sidemember, also as shown. In some implementations, the respective anglesbetween the arms and the side members may be less than 15 degrees andthe respective angles between the rigid case and the side members arealso less than 15 degrees. Other angles are possible as well, asrelatively larger wheel diameters may allow larger angles between thecomponents.

FIG. 2B is then an illustration of the robotic chassis 200 in aninstance of a “case-forward” configuration. In the case-forwardconfiguration, a front side of the rigid case 206 is facing away fromarm 208A and 208B. In such a configuration, a front-facing camera of atablet computer that is arranged in the mounting point of the rigid case206 may provide a first-person viewpoint from a perspective of therobotic chassis 200.

In some circumstances, a control system, such as control system 102, maycause the robotic system to transform into the case-forwardconfiguration. Such a transformation may involve rotating the distalends of the arms above the proximal ends of the arms such that the armsare at respective angles to the first side member and the second sidemember and rotating the distal end of the rigid case above the proximalend of the rigid case such that the rigid case are at respective anglesto the first side member and the second side member.

FIG. 2C next illustrates the robotic chassis 200 in an instance of an“arms-forward” configuration. In the arms-forward configuration, therigid case 206 and the arms 208A and 208B are at respective angles tothe first side member 202A and the second side member 202B. In such aconfiguration, arms 208A and 208B may show in a viewpoint of afront-facing camera on a tablet mounted in the rigid case 206, which mayprovide indicate the orientation of the robotic chassis 202 relative tothe viewpoint of the front-facing camera.

In some circumstances, a control system, such as control system 102, maycause the robotic system to transform into the arms-forwardconfiguration. Such a transformation may involve rotating the respectivedistal ends of arm 208A and 208B above the respective proximal ends ofarm 208A and 208B such that the arms are at respective angles to thefirst side member and the second side member. The respective angles maybe within a range from about 75 degrees to about 150 degrees. Thetransformation may further involve rotating the distal end of the rigidcase above the proximal end of the rigid case. After such a rotation,respective angles between the rigid case and the first side member andthe second side member may be within a range from about 85 degrees toabout 105 degrees. Such angles may position the rigid case 206 and thearms 208A and 208B such that the arms 208A and 208B show in a viewpointof a front-facing camera on a tablet mounted in the rigid case 206.

FIG. 3A is a deconstructed view of the example rigid case 206. Rigidcase 206 includes a front shell 206A and a rear shell 206B. The frontshell 206A and the rear shell 206B may be connectable by latches,perhaps at one or more latch points. As noted above, when connected, thefront shell 206A and rear shell 206B may define a volume in which atablet computer may be mounted. For instance, the rear shell 206B mayhave a recessed cavity in which the tablet computer 306 may be placed.In such an example, mounting the tablet computer 306 may involve placingthe tablet computer 306 into a rear shell 206B (which is rotatablycoupled to the robotic chassis 200). The front shell 206A may then beplaced on the rear shell 206B and latched to the rear shell 206B tocontain the tablet computer 306.

The front shell 206A and the rear shell 300B may have various openings,which may facilitate operation of various components of a mounted tabletcomputer. For example, the front shell includes an opening 302A, whichis configured to expose a touchscreen display of the tablet computer.The rear shell includes an opening 302B, which is configured to expose arear-facing camera of the tablet computer and perhaps also anillumination device (e.g., one or more LEDs). Alternate sizes, shapes,and configurations of openings are possible and may depend on the tabletcomputer implemented in the robotic system. The openings may be coveredby a sealed transparent window, which may provide water-resistance. Insome cases, the rigid case 206 may be made of a transparent materialsuch that various components of the tablet computer may operate throughthe case.

In some cases, a second instance of the tablet computer may be mountedin a second rigid case. In some implementations, the other rigid casemay be a second instance of the rigid case. As noted above, in somecases, a second instance of the tablet computer may be used as acontroller to the robotic system. To facilitate such a use, handles maybe mounted on the second rigid case. For instance, a left handle and aright handle may be mounted on the left side and the right side of therigid case 206, respectively. Such handles may provide surfaces thatfacilitate gripping of the tablet computer. Such handles may also haveinterior volumes that, when connected to the rigid case, may make therigid case buoyant in some circumstances. Further, the handles may alsoreduce or eliminate damage from impacts. Such impact resistance may beenhanced in some cases by bumpers placed on one or more corners of thehandles. To further facilitate control of the robotic system by a secondinstance of the tablet computer, the handles may include variouscontrols, such as buttons or joysticks. Input from these controls may betranslated into commands for the robotic system.

FIG. 3B illustrates an example arrangement of rigid case 206 in whichthe front shell 206A is hinged to the rear shell 206B. In such anarrangement, mounting the tablet computer 306 may involve rotating thefront shell 206A away from the rear shell 206B about an axis that isformed by the hinges. In some cases, the rigid case 206 may includehinges on one edge and latches on the opposite edge. In other cases, therigid case 206 may include latches on two (or more edges) and a subsetof the latches may operate as hinges (i.e., allow the front shell 206Ato rotate relative to the rear shell 206B).

The front shell 206A and/or the rear shell 206B may include respectivegaskets. For instance, the front shell 206A may include gaskets 304A and304B. Such gaskets may aid in preventing water damage to the tabletcomputer, as such gaskets may prevent water from coming into contactwith certain parts of the tablet computer (e.g., seams into which watermay seep). Additional environmental protection features may be includedas well.

As noted above, mounting may further involve placing the tablet computeron the rear shell 206B. FIG. 3C illustrates the tablet computer 306after being placed on the rear shell 206B. Then, the front shell 206Amay be rotated towards from the rear shell 206B so that the front shell206A may be latched to the rear shell 206B.

FIG. 4 is a flowchart illustrating example operations that may positiona robotic device.

At block 402 in FIG. 4, the method may involve determining a plan tomove a robotic chassis to a target position. For instance, controlsystem 102 of FIG. 1 (perhaps implemented as one or more components of atablet computer) may determine a plan to move the robotic chassis to atarget position. The target position may include a target orientation, atarget height, and/or a target location, among other examples.

In some examples, the determined target position may include a targetorientation, target height, and/or target location of a tablet computer,as positioning a tablet computer may be advantageous in somecircumstances. For instance, a tablet computer may be mounted in amounting point of a rigid case. The tablet computer may have one or moresensors (e.g., one or more sensors of sensing system 110) and moving thetablet computer to the target position may alter respective perspectivesof the sensors. After positioning the tablet computer in the targetposition, the sensors may produce data from the perspective of thetarget position.

For instance, the tablet computer may have a front-facing camera, andmoving the tablet computer to the target position may point thefront-facing camera at one or more objects that are to be the subject ofa photograph or video captured by the front-facing camera. As onepossible application is in home security in which a robotic system mayposition a camera at various heights, orientations, and locations tomonitor a home. As another application, a robotic system may determine aplan to move to one or more target positions that are suitable fortelepresence. As a further application, the control system may determineone or more target positions at which to observe a pet. Otherapplications are possible as well.

The tablet computer may determine a plan based on one or more receivedcommands. For instance, the tablet computer may receive one or morecommand by way of a communication interface, such as communicationinterface 112. Such commands may direct the robotic system to performvarious tasks, such as those noted above, among other examples. In otherexamples, the commands may indicate one or more aspects of the targetposition, such as a target height, a target location, or a targetorientation, among other examples.

In some cases, the determined plan may be based on one or more featuresof the environment in which the robotic system is operating. Forinstance, the robotic system may detect the one or more features andthen determine a plan to navigate up to, over, or around such features.In one example, the robotic system may detect a window and thendetermine a plan to position a camera of a tablet computer of therobotic system such that it is pointed out the window.

In other cases, the determined plan may be based on a state orconfiguration of the robotic system. As one example, the robotic systemmay detect that it is stuck, hung up, or otherwise obstructed by one ormore features of the environment. For instance, perhaps based on IMU orGPS data the robotic system may detect that it is not moving relative tothe environment despite causing the wheels to rotate. In such aninstance, the determined plan may involve freeing the robotic chassisfrom the one or more features that may be obstructing the roboticchassis. In another example, the robotic system may detect that therobotic chassis is flipped upside down, and the determined plan mayinvolve flipping the robotic chassis over. Other examples are possibleas well.

FIG. 5 is a perspective view of the robotic chassis 200 in an exampletarget position. An instance of method 400 may position the roboticchassis 200 in such an example target position. This target position maybe used to raise a tablet computer above a support surface, therebyraising respective perspective of one or more sensors of the tabletcomputer. Raising the respective perspective of the one or more sensorsmay have advantages for various applications, such as telepresence,security, or search and rescue.

Referring back to FIG. 4, at block 404, the method may involveinitiating a rotation of a rigid case. For instance, control system 102of FIG. 1 may initiate a rotation of the rigid case 206 of FIG. 2A, 2B,or 2C. Such a rigid case may have a proximal end that is rotatablycoupled between respective side members of the robotic chassis atrespective first ends of the side members between the side members abouta first transverse axis, as shown by rigid case 206 relative to sidemembers 202A and 202B. One or more actuators may drive the rotation ofthe rigid case about the first transverse axis.

The implementation may also involve initiating a rotation of one or moreof a first arm and a second arm. For instance, a control system mayinitiate a rotation of arms 208A and 208B about a second transverse axisthat is parallel to the first transverse axis. The arms may be rotatablycoupled outside of the respective side members of the robotic chassis atrespective second ends of the side members, as shown by arms 208A and208B in FIG. 2A, 2B, or 2C. The control system may rotate the first armand the second arm in respective clockwise or counterclockwisedirections about the second transverse axis. In one example, the controlsystem may initiate a rotation of the arms downward towards a supportsurface. Contact between the arms and support surface may liftrespective ends of the side members upward relative to the respectivesecond ends of the side members. One or more actuators may drive therotation of the arms about the second transverse axis.

FIG. 6A shows a side view of an example robotic chassis 600 in a firststage of a sequence to position the robotic chassis 600 in a targetposition in which the rigid case is perpendicular to and lifted above asupport surface. Robotic system 600 includes a frame 602, arms 604, arigid case 606 (not shown), and first wheels 608A and second wheels 608Bmounted at opposite ends of the frame 602. In FIG. 6A, a tablet computer(or other control system) has initiated respective rotations of the arms604 downward toward a support surface, as shown. Contact by the arms 604with the support surface has lifted a first end (i.e., an end to whichwheels 608A are coupled) of the robot chassis 600 off of the supportsurface.

While rotating the arms 604 downward, the tablet computer may retard therotations of wheels 608B. Such an operation may hold the frame 602 inposition relative to the support surface while the arms 604 are liftingthe first end of the robot chassis 600 off of the support surface (i.e.,prevent the robotic chassis 600 from moving to the left). In oneexample, the tablet computer may cause an actuator to retard rotation ofthe wheels 608B. Alternatively, the tablet computer may cause a brake toretard the rotation of the wheels 608B. Other examples are possible aswell.

FIG. 6B shows a side view of the example robotic chassis 600 in a secondstage of the sequence to position the robotic chassis 600 in the targetorientation. Compared to FIG. 6A, the arms 604 have further rotated tolift the first end of the frame 602 higher relative to the supportsurface. Such a rotation also lifts the rigid case 606 further above thesupport surface, thereby altering the position of the tablet computer.The tablet computer has also initiated a rotation of the rigid case 606,as shown. Such a rotation may change the height and orientation of atablet computer mounted in the rigid case. The arms 604 and the rigidcase 606 are capable of rotating concurrently because the arms 604rotate outside of the frame and the rigid case 606 rotates inside theframe (e.g., between respective side members, as shown in FIGS. 2A, 2B,and 2C).

Referring back to FIG. 4, at block 406, the method may involvedetermining that the tablet computer is at the target orientation basedon data from at least one orientation sensor of the tablet computer. Theorientation sensor may be any suitable sensor configured to generatedata indicative of orientation, such as an accelerometer or IMU ofsensing system 110. Within examples, the tablet computer (or othercontrol system) may receive such data at various intervals, such asperiodically, or perhaps when data from the sensor is available. Afterreceiving such data, the tablet computer may determine whether or notthe tablet computer is at the target orientation. For instance, thetablet computer may compare an orientation indicated by the data to thetarget orientation.

After initiating the rotation of the rigid case about the secondtransverse axis, the implementation may involve determining that thetablet computer is at the target height. Such a determination may bebased on data from at least one height sensor of the tablet computer.The height sensor may include an accelerometer or an IMU of the tabletcomputer, among other examples. After receiving data from such a sensor,the tablet computer may compare a height indicated by the data to thetarget height, and determine that the tablet computer is at the targetheight (or perhaps that the tablet computer is at a height other thanthe target height).

FIG. 6C shows a side view of the example robotic chassis 600 in a thirdstage of the sequence to position the robotic chassis 600 in the targetorientation. Compared to FIG. 6B, the arms 604 have further rotated tolift the first end of the frame 602 higher relative to the supportsurface and up to the target height. The rigid case 606 has furtherrotated to the target orientation in which the rigid case isperpendicular to the support surface.

In some implementations, the tablet computer may determine that othercomponents of the robotic system are at respective target positions.Such a determination may be made in addition to the determinations notedabove or as an alternative to such determinations. In one example, therobotic system may include one or more second sensors that are not partof the tablet computer. Such sensors may be mounted to a frame of therobotic system, or on one or more arms of the robotic system, amongother alternatives. The tablet computer may rotate various components ofthe robotic device to position such second sensors at respective targetpositions.

At block 408 in FIG. 4, the method may involve halting the rotation ofthe rigid case about the first transverse axis to position the tabletcomputer in the target orientation. For instance, in response todetermining that the tablet computer is at the target orientation, thetablet computer may halt the rotation of the rigid case. Halting therotation may involve causing one or more actuators that are configuredto rotate the rigid case to stop rotating the rigid case and hold therigid case in the target orientation. For instance, referring back toFIG. 6C, the tablet computer may halt the rotation of the arms 604 atthe target height. Further, the tablet computer may halt the rotation ofthe rigid case 606 at the target orientation. These operations mayfacilitate positioning the tablet computer at the target position.

As noted above, in some cases, the target position may involve a targetlocation. In such an example, the plan to move the robotic chassis tothe target position may further include a path to a target location. Therobotic system may then move to the target location as part ofpositioning the tablet computer in the target position. In one example,a tablet computer may cause one or more wheels (e.g., wheels 210A, 210B,210C, and/or 210D) to rotate and thereby move the robotic chassis alongthe path to the target location. After causing the one or more wheels torotate, the tablet computer may determine that the tablet computer is atthe target location based on data from at least one location sensor ofthe tablet computer (e.g., a GPS sensor). Then, in response todetermining that the tablet computer is at the target location, thetablet computer may halting the rotation of the one or more wheels toposition the tablet computer at the target location.

FIG. 7A shows the robotic chassis 200 in an example environment 700 thatincludes a path to a target location 704 around an obstacle 704. Thetablet computer may determine the path based on data from one or moresensors. For instance, the tablet computer may detect the obstacle 704by way of one or more perception sensors such as a lidar system, astereocamera, and/or a rangefinder. Then, perhaps based on GPS data(e.g., by way of GPS navigation) or IMU data (e.g., by way of deadreckoning), the tablet computer may determine the path to the targetlocation.

FIG. 7B next shows the robotic chassis 200 after the tablet computercauses the robotic chassis 200 to navigate to the target location 702.Further, the tablet computer has caused the rigid case 206 and arms 208Aand 208B to rotate to bring the rigid case (containing the tabletcomputer) to a target height and target orientation. In such a targetposition, a rear-facing camera of the tablet computer may captureimaging data through the window 706.

After positioning the rigid case in the target position, the tabletcomputer may cause at least one sensor of the tablet computer to capturesensor data from a perspective of the target position. As noted above,such data capture from a target position may have various applications,including home security, telepresence, and search and rescue, amongother examples. In one example, after positioning the tablet computer atthe target position, the tablet computer may cause a perception sensor(e.g., a camera) to generate imaging data from a perspective that isparallel to the target orientation.

FIG. 8 is next a flow chart illustrating another example method forpositioning a tablet computer in a target position. This example methodmay be used in combination with a plan to move to a target position(e.g., as noted above in connection with FIG. 4 and method 400) or themethod may be used in connection with commands that cause a roboticsystem to position a tablet computer in a target position. For instance,a robotic system may receive commands over a network interface thatcause the robotic system to position a tablet computer in a targetposition.

At block 802, a controller of a robotic device (e.g., a tablet computermounted in the rigid case) may determine a target position for a rigidcase having a proximal end that is rotatably coupled between sidemembers of a frame of the robotic device at respective first ends of theside members. As noted above, a target position may include variouscomponents, such as a target height of the rigid case from a supportsurface or a target angle between the rigid case and the supportsurface.

At block 804, the controller may cause the rigid case to rotate betweenthe side members about a first transverse axis to orient the rigid caseat a target angle between the rigid case and the support surface. Forinstance, a tablet computer may cause rigid case 206 of robotic chassis200 to rotate between side members 202A and 202B to orient rigid case206 at a target angle.

At block 806, the controller may cause a first arm and a second arm thatare rotatably coupled to the robotic device at the respective secondends of the side members to rotate outside the side members and downwardtowards the support surface about a second transverse axis that isparallel to the transverse member and to the first transverse axis. Sucha rotation may lift the rigid case upwards to the target height of therigid case from the support surface. For instance, a tablet computer maycause arms 208A and 208B to rotate and thereby lift the robotic chassis200 or a portion thereof.

As noted above, FIGS. 4 and 8 are flowcharts illustrating exampleoperations that may position a robotic device. These operations, forexample, could be used with the robotic system 100 in FIG. 1 or therobotic chassis 200 in FIG. 2A, 2B, or 2C, for example, or may beperformed by a control system (e.g., a control system within a chassisor communicatively coupled to the chassis, such as a tablet computerincluding a control system) or a combination of any components of therobotic system 100 in FIG. 1 or the robotic chassis 200 in FIG. 2A, 2B,or 2C. FIGS. 4 and 8 may include one or more operations, functions, oractions as illustrated by one or more of blocks 402-408 and 802-806.Although the blocks are illustrated in a sequential order, these blocksmay in some instances be performed in parallel, and/or in a differentorder than those described herein. Also, the various blocks may becombined into fewer blocks, divided into additional blocks, and/orremoved based upon the desired implementation.

In addition, for FIG. 4, FIG. 8, and other processes and methodsdisclosed herein, the flowchart shows functionality and operation of onepossible implementation of present implementations. In this regard, eachblock may represent a module, a segment, or a portion of program code,which includes one or more instructions executable by a processor forimplementing specific logical functions or steps in the process. Theprogram code may be stored on any type of computer-readable medium, forexample, such as a storage device including a disk or hard drive. Thecomputer-readable medium may include a non-transitory computer-readablemedium, for example, such as computer-readable media that stores datafor short periods of time like register memory, processor cache andrandom access memory (RAM). The computer-readable medium may alsoinclude other non-transitory media, such as secondary or persistent longterm storage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. Thecomputer-readable media may also be any other volatile or non-volatilestorage system. The computer-readable medium may be considered acomputer-readable storage medium, a tangible storage device, or otherarticle of manufacture, for example. The program code (or data for thecode) may also be stored or provided on other media includingcommunication media. For instance, the commands may be received on awireless communication media, for example.

In addition, for FIG. 4, FIG. 8, and other processes and methodsdisclosed herein, each block may represent circuitry that is arranged toperform the specific logical functions in the process.

Functions of FIG. 4 and FIG. 8 may be fully performed by one controlsystem, or may be distributed across multiple control systems (e.g.,among two or more tablet computers that are communicatively coupled toone another). In some examples, the control system may receiveinformation from sensors of a robotic system, or the control system mayreceive the information from a processor that collects the information.The control system could further communicate with a remote controlsystem (e.g., a control system on another robotic device) to receiveinformation from sensors of other devices, for example.

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g. machines,interfaces, functions, orders, and groupings of functions, etc.) can beused instead, and some elements may be omitted altogether according tothe desired results. Further, many of the elements that are describedare functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in anysuitable combination and location, or other structural elementsdescribed as independent structures may be combined.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular implementations only, and is not intended to belimiting.

What is claimed is:
 1. A robotic chassis, comprising: a frame comprisinga first side member and a second side member connected by a transversemember near respective first ends of the first side member and thesecond side member; a rigid case having a distal end and a proximal end,wherein the proximal end of the rigid case is rotatably coupled betweenthe first side member and the second side member near respective secondends of the first side member and the second side member, and whereinthe rigid case comprises a mounting point for a tablet computer; a firstarm and a second arm having respective distal ends and respectiveproximal ends, wherein the respective proximal ends of the first arm andthe second arm are rotatably coupled to the frame near respective firstends of the first side member and the second side member; a plurality ofwheels rotatably coupled to the frame; and a control system configuredto cause the robotic chassis to transform into a case-forwardconfiguration in which a front side of the rigid case is facing awayfrom the arms, wherein transforming into the case-forward configurationinvolves rotating the distal ends of the arms above the proximal ends ofthe arms.
 2. The robotic chassis of claim 1, wherein the plurality ofwheels comprises at least one first wheel rotatably coupled to the firstside member and at least one second wheel rotatably coupled to thesecond side member.
 3. The robotic chassis of claim 1, wherein theplurality of wheels comprise a first forward wheel and a second forwardwheel near the respective first ends of the first side member and thesecond side member; the first forward wheel and the second forward wheelare rotatable about respective axles; the axles comprise respective axleshafts, respective proximal axle ends, and respective distal axle ends;and the first arm and the second arm are rotatably coupled to therespective distal axle ends of the respective axles.
 4. The roboticchassis of claim 1, wherein the mounting point comprises: a front shellhaving an opening, whereby a display of the tablet computer is viewablethrough the opening; and a rear shell that is attachable to the frontshell, whereby the tablet computer is engageable between the front shelland the rear shell by attachment of the rear shell to the front shell.5. The robotic chassis of claim 1, further comprising: at least onefirst actuator connected to the rigid case, wherein the at least onefirst actuator is configured to rotate the rigid case relative to theframe; at least one second actuator connected to the arms, wherein theat least one second actuator is configured to rotate the arms relativeto the frame; at least one third actuator configured to rotate one ormore of the wheels; and a communication interface configured tocommunicatively couple the at least one first actuator, the at least onesecond actuator, and the at least one third actuator to the tabletcomputer.
 6. The robotic chassis of claim 1, wherein a width of therigid case extends approximately from the first side member to thesecond side member.
 7. The robotic chassis of claim 1, wherein a lengthof the rigid case from the proximal end of the rigid case to the distalend of the rigid case is shorter than a length of the side members. 8.The robotic chassis of claim 1, wherein a diameter of the wheels isgreater than a depth of the rigid case.
 9. The robotic chassis of claim1, wherein the first side member and the second side member have a firstlength, and wherein the first arm and the second arm have a secondlength that is approximately equal to the first length.
 10. The roboticchassis of claim 1, wherein the rigid case, the first arm, the secondarm, and the plurality of wheels are rotatable about respective paralleltransverse axes.
 11. A robotic chassis, comprising: a frame comprising afirst side member and a second side member connected by a transversemember near respective first ends of the first side member and thesecond side member; a rigid case having a distal end and a proximal end,wherein the proximal end of the rigid case is rotatably coupled betweenthe first side member and the second side member near respective secondends of the first side member and the second side member, and whereinthe rigid case comprises a mounting point for a tablet computer; a firstarm and a second arm having respective distal ends and respectiveproximal ends, wherein the respective proximal ends of the first arm andthe second arm are rotatably coupled to the frame near respective firstends of the first side member and the second side member; a plurality ofwheels rotatably coupled to the frame; and a control system configuredto cause the robotic chassis to transform into a stowed configuration,wherein transforming into the stowed configuration involves: rotatingthe arms next to and substantially parallel with the first side memberand the second side member such that respective angles between the armsand the first side member and the second side member are less than 15degrees; and rotating the rigid case next to and substantially parallelwith the first side member and the second side member such thatrespective angles between the rigid case and the side members are lessthan 15 degrees.
 12. The robotic chassis of claim 11, wherein theplurality of wheels comprises at least one first wheel rotatably coupledto the first side member and at least one second wheel rotatably coupledto the second side member.
 13. The robotic chassis of claim 11, whereinthe plurality of wheels comprise a first forward wheel and a secondforward wheel near the respective first ends of the first side memberand the second side member; the first forward wheel and the secondforward wheel are rotatable about respective axles; the axles compriserespective axle shafts, respective proximal axle ends, and respectivedistal axle ends; and the first arm and the second arm are rotatablycoupled to the respective distal axle ends of the respective axles. 14.The robotic chassis of claim 11, wherein the mounting point comprises: afront shell having an opening, whereby a display of the tablet computeris viewable through the opening; and a rear shell that is attachable tothe front shell, whereby the tablet computer is engageable between thefront shell and the rear shell by attachment of the rear shell to thefront shell.
 15. The robotic chassis of claim 11, further comprising: atleast one first actuator connected to the rigid case, wherein the atleast one first actuator is configured to rotate the rigid case relativeto the frame; at least one second actuator connected to the arms,wherein the at least one second actuator is configured to rotate thearms relative to the frame; at least one third actuator configured torotate one or more of the wheels; and a communication interfaceconfigured to communicatively couple the at least one first actuator,the at least one second actuator, and the at least one third actuator tothe tablet computer.
 16. A robotic chassis, comprising: a framecomprising a first side member and a second side member connected by atransverse member near respective first ends of the first side memberand the second side member; a rigid case having a distal end and aproximal end, wherein the proximal end of the rigid case is rotatablycoupled between the first side member and the second side member nearrespective second ends of the first side member and the second sidemember, and wherein the rigid case comprises a mounting point for atablet computer; a first arm and a second arm having respective distalends and respective proximal ends, wherein the respective proximal endsof the first arm and the second arm are rotatably coupled to the framenear respective first ends of the first side member and the second sidemember; a plurality of wheels rotatably coupled to the frame; and acontrol system configured to cause the robotic chassis to transform intoan arms-forward configuration in which a front side of the rigid case isfacing the arms, wherein transforming into the arms-forwardconfiguration comprises: rotating the distal ends of the arms above theproximal ends of the arms such that the arms are at respective angles tothe first side member and the second side member, wherein the respectiveangles are within a range from about 75 degrees to about 150 degrees;and rotating the distal end of the rigid case above the proximal end ofthe rigid case such that respective angles between the rigid case andthe first side member and the second side member are within a range fromabout 85 degrees to about 105 degrees.
 17. The robotic chassis of claim16, wherein the plurality of wheels comprises at least one first wheelrotatably coupled to the first side member and at least one second wheelrotatably coupled to the second side member.
 18. The robotic chassis ofclaim 16, wherein the plurality of wheels comprise a first forward wheeland a second forward wheel near the respective first ends of the firstside member and the second side member; the first forward wheel and thesecond forward wheel are rotatable about respective axles; the axlescomprise respective axle shafts, respective proximal axle ends, andrespective distal axle ends; and the first arm and the second arm arerotatably coupled to the respective distal axle ends of the respectiveaxles.
 19. The robotic chassis of claim 16, wherein the mounting pointcomprises: a front shell having an opening, whereby a display of thetablet computer is viewable through the opening; and a rear shell thatis attachable to the front shell, whereby the tablet computer isengageable between the front shell and the rear shell by attachment ofthe rear shell to the front shell.
 20. The robotic chassis of claim 16,further comprising: at least one first actuator connected to the rigidcase, wherein the at least one first actuator is configured to rotatethe rigid case relative to the frame; at least one second actuatorconnected to the arms, wherein the at least one second actuator isconfigured to rotate the arms relative to the frame; at least one thirdactuator configured to rotate one or more of the wheels; and acommunication interface configured to communicatively couple the atleast one first actuator, the at least one second actuator, and the atleast one third actuator to the tablet computer.